I've got an account with a survey website. If you take a survey, it gives you virtual currency. You can't cash out, per se, but you can spend that virtual currency on real world stuff.
Originally, I got the account so I could boost my frequent flier miles with Continental. Last year, they had Gamestop gift cards, so I got a couple of those. This year, there's really not a whole lot I want.
I could continue buying airline miles that I probably won't use for a very long time (no job right now, and when I do get one, it'll be a year before I can take a vacation). I could also get a half-year subscription to The Economist, or a bunch of issues of the Wall Street Journal. I don't like any of the other magazines they have up right now. Or... I could save more, and buy even more airline miles, or save up for a full year of The Economist.
I don't even know if I'd like The Economist, and I don't know if I want a newspaper subscription right now.